Anti–PD-1–Related Pneumonitis during Cancer Immunotherapy

The use of antibodies against programmed cell death 1 (PD-1), which block inhibitory T-cell checkpoints, is a promising new therapy for advanced cancers.1 Recent trials have shown substantial clinical activity of anti–PD-1 antibodies in advanced cancers and led to the approvals of these agents, including pembrolizumab for melanoma and nivolumab for melanoma and squamous-cell lung cancer.2-4 Pneumonitis related to the use of antibodies against PD-1 is an immune-mediated toxic effect that resulted in three drug-related deaths in a phase 1 trial.1 Clinical identification and management of pneumonitis are contingent on radiographic assessment. We report three cases of pneumonitis associated with the use of anti–PD-1 antibodies in patients with melanoma